We used fast.com to speed test our new office internet connection and the next day got an irate email from corporate (who had argued we didn't need the new connection) about "watching Netflix all day". I imagine some C-level thought they had a real gotcha! moment until I showed them the site.

I read a while ago that certain ISPs will optimize the traffic to Netflix's servers, and so when you run fast.com (which is my default, by the way), you get your Internet speed for watching Netflix, but not necessarily for other things.